Increase dash version to 2.10 or greater

[delsim]

The dash version is currently limited to <2.10 as django-plotly-dash uses an internal API that is no longer present in 2.10 Refactoring of the code to avoid this (and any other steps) are needed to move to this version and beyond.

[Nizhurin]

It will be pretty cool if You can upgrade to dash > 2.0

[mmc1718]

What would need doing to support more recent versions of Dash? Is #485 enough? I assume some code changes are required